U.S. Pat. No. 4,392,187 (hereinafter '187), having a common inventor to the present application, describes a stage lighting system that is used to project a high intensity beam of light having certain variable characteristics such as shape, color and position. In '187, a high intensity discharge lamp provides a compact source of white light. The white light is colored by a dichroic color changing system that allows producing a large range of different colors. The colors, as well as other properties of the light, can be controlled using a digital control architecture. The digital control architecture allows transmitting commands from a central control console to the light.
Different kinds of light and colors of light can be produced by this kind of system.